<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>ondblclick</title>
    <script>
    function copyText(){
        alert("双击两下")
    }    
    </script>
    
</head>
<body>
    <input type="button"  ondblclick="copyText()" value="双击">
    
</body>
</html>